The element (Joppa element number #E120-06-205) is shown entering the kiln cavity in the rear through two lead tubes. The element proceeds through the kiln space in a "U" shape supported on 1/4" mulite rods that are 15" long. Each mulite rod is supported with two donuts, and those donuts are held in place by a wire that is wrapped around the groove in the middle of the donut. This support wire is pulled through the insulation using a donut needle and attached to the outside of the kiln in much the same way as the frax pigtails are attached.

Next, is the switch end of the kiln. Here is a general overview shot of the project. The image shows an infinite switch, but you could substitute a toggle switch. I would recommend having some kind of "kill switch" just in case something goes wrong.

Below is a view of the wiring in the 4" box, with the cover removed. For a more detailed view of this component study figure 19-8 on page 96 of A Glassblower's Companion. Figure 19-8 is an in-depth schematic of the situation here at hand. Also look at marinite connection boards.

Here is the simple electrical diagram of the mailbox project.